1. Field of the Invention
The present invention relates generally to tape libraries using auxiliary memory devices contained in tape storage cartridges in tape libraries to record information related to available tape cartridge storage space.
2. Description of Related Art
Data storage libraries, such as tape libraries, are typically used to store and retrieve large amounts of data for data manipulation and archiving purposes. These libraries are generally comprised of drive devices adapted to read and write data to and from tape cartridges that are often housed within the tape libraries. In the interest of obtaining cursory information about a specific tape cartridge without requiring a time-consuming media load and tape threading process to read the on-tape index file, techniques using holes arranged in patterns in the cartridge casing and later electrical pads grounded in a variety of combinations were introduced. The holes and/or electrical pads provided simple information such as tape capacity, manufacturer, etc. Today, these techniques are yielding to the introduction of Radio Frequency chips disposed in the tape cartridges called a Memory-In-Cartridge (MIC) or Medium Auxiliary Memory (MAM), because of increased amounts of information and ease of use. FIG. 1A shows an example of a tape cartridge 100, tape medium 102, and MIC 104, shown here in dashed lines because the MIC 104 and tape medium 102 reside in the interior of the cartridge 100. In this example, the MIC is disposed in an LTO-3 cartridge which can be provided by TDK Corp. of Tustin, Calif.
A MIC allows the tape drive to access valuable cartridge data without the use of a physical connection, reducing connector wear for both the drive and the media. The MIC is a memory chip built into the data cartridge that provides a direct and immediate connection to the drive's on-board processors, which speeds access to information related to the data cartridge such as system logs, for example. Information and file search parameters are formatted within the MIC system effectively cutting the data access time down to a fraction from historical techniques.
As shown in FIG. 1B, a MIC 104 fundamentally comprises an integrated circuit that includes solid state memory and a transponder 124 attached to an antenna 126, the antenna is typically a small coil of wires. The MIC 104 is considered a passive device because it is energized when subjected to a strong enough RF field produced by a MIC-Reader. Information can be transmitted between the MIC and the MIC-Reader via a specific radio frequency.
Currently a MIC, or MAM, is parceled into regions for a medium, device and host. The three regions can accommodate attributes related to a medium with a MIC. For example a medium attribute can be a serial number permanently stored in the MAM during manufacturing, a device attribute can be load count maintained by the tape drive and a host attribute can be a backup date maintained by the application client. These attributes are strictly read and written to by a reader disposed in a drive.
In an effort to expand capabilities of a storage element containing a MIC operable with a data storage unit as it pertains to available storage space in a cartridge and/or library at substantially any given time, both methods and apparatus are disclosed herein. It is to innovations related to this subject matter that the claimed invention is generally directed.